This invention relates generally to the field of electrical power generation by utilizing, as the prime mover, an impulse turbine, which is part of the family of tangential water wheels. The turbine is capable of being constructed in various sizes ranging from several inches in diameter to 30 feet or more, and from a few inches in width to several feet. A typical high torque turbine would be 20 feet in diameter and 5 or 6 feet in width. A horizontal axle is fixed to the turbine and rotates with it. Ideally, incoming water approaches a runner portion of the turbine in an undershot or a breastshot manner similar to the prior art Poncelet wheel, but the turbine may be adapted to an overshot condition or to a combination of approach angles.
The incoming water pushes against blades or buckets which are an integral part of the runner portion of the turbine and thereby produces rotation. The runner is designed to retain water for a portion of each revolution, unlike the Pelton turbine which deflects the water. To enhance retention of water, the turbine is fitted with a breastplate undercarriage which is connected to the incoming water source. The breastplate is not connected to the turbine and does not rotate.
The high torque turbine rotates relatively slowly, achieving a top speed in most cases of 45 to 60 r.p.m., and utilizes a speed increaser before connecting to a generator.
The incoming water ideally is provided by pipes or penstocks and, depending on the width of the runner, the water can be diffused through a manifold arrangement providing more than one inlet through the breastplate.
Incoming water approaches the runner tangentially and imparts all or nearly all of its energy to the runner in a tangential direction. The water travels tangentially after engaging the runner and does not substantially change direction. The water exists the runner/breastplate area at an angle combining tangential and outward flow away from the axle. The runner is designed to receive incoming water with near zero impact and discharge water with near zero forward velocity.
All of the energy transferred to the turbine from the water occurs in the outer portion of the turbine and thereby produces a high torque on the axle. The high torque turbine differs from the prior art Poncelet water wheel in the following ways:
1) The Poncelet water wheel was popularly used in the mid 1800's. Since then, technology advances have provided for improved materials and manufacturing processes such as close tolerance machining; the use of precision bearings producing a balanced rotation with decreased friction losses; and durability with minimum maintenance. PA1 2) Incoming water is provided to the high torque turbine via one or more penstocks/pipes. PA1 3) The high torque turbine offers an improved runner design which reduces or eliminates axial thrust. PA1 4) The high torque turbine rotates faster than the Poncelet wheel and accommodates a higher head and flow rate. PA1 5) The high torque turbine is the prime mover for producing electricity. PA1 6) The high torque turbine is intended to be mounted on the face of a dam or adjacent to a dam near the tailwater area or near a river. PA1 7) In its preferred form, the high torque turbine is wider than the Poncelet wheel and larger in diameter. PA1 1) The high torque turbine retains water rather than deflecting it. PA1 2) The high torque turbine runner design is simpler and more economical to manufacture. PA1 3) The high torque turbine can accomodate higher flow rates and lower head ranges. PA1 4) The high torque turbine is designed to rotate slowly. PA1 5) The high torque turbine utilizes a breastplate to help it retain water. PA1 6) The high torque turbine utilizes a simplified water distribution system and does not require nozzles. PA1 7) The high torque turbine is intended for external use and can be installed with or without a housing. PA1 8) The high torque turbine utilizes a speed increaser whereas the Pelton generally does not.
The high torque turbine differs from the prior art Pelton turbine in the following ways.